Swing-joint for lighting-fixtures.



E. 0. WHITE.

SWING JOINT FOR LIGHTING FIXTURES.

APPLICATION FILED JUNE 3.1915.

1,279,807. Patented Sept. 24,1918.

Attest: Inventor: wq i/ by M Q I 1M Attys.

RS m. Pnomumm. WAsnmcmn. 01 k;

UNITED sT TEs TENT oEEIoE.

ERNEST 0. WHITE, or WEsTMoUNT, CANADA, AssIeNon, BY MESNE .AssIeNMENTs,To v DUPLEXALITE CORPORATION, OF NEW YORK, N. Y., A CORPORATION or NEWYORK.

Application filed June 3, 1915.

To all whom it may concern: I

Be it known that I, ERNEsT O. VVi-IITE, a citizen of the United States,residing at VVestmount, Canada, have invented certain new and usefulImprovements in Swing- Joints for Lighting-FiXtures, of which thefollowing is a specification, reference being had to the accompanyingdrawings, forming a part hereof.

In an application filed by the present ap-' plicant on March 31, 1915,Ser. No. 18,221, there is shown and described a lighting fixture inwhich there is provided a fixed source of lightand an invertiblereflector, whereby the fixture may be converted from one in which therays of light are thrown to the ceiling, as in the indirect lightingsystem, to one in which the rays of light are permitted to fall directly011 the object, as in the direct lighting system. The present inventionis concerned broadly with a fixture of this general type but seeksparticularly to provide a convertible fixture which shall be peculiarlyadapted for use under conditions where the other fixture, for somereason, is not desirable. In the present invention, the source of lightis not fixed as before but is movable bodily with the invertiblereflector during the conversionof the fixture for use in accordance withone or the other of the above named systems. The mere inversion of areflector with its source of light is now well known and accordingly noclaim is made broadly thereto. Known fixtures of this character,however, are maintained in normal position or in inverted position bymeans'of positive retaining devices which require especial manipulationby the user. Further, therelectrical wiring in such known fixtures asthese has been subjected to abnormal twisting and bending strains or hasrequired separate manipulation by the user to avoid such strains. Theseold structures are unsatisfactory principally inthe respects noted andthe broad objects of the present invention, accordingly, are, first, toprovide an invertible fixture in which the source of light is movablewith the reflector and in whiehthe source of. light and the reflectorare swung from normal position to inverted position about anaxis'coincident with the centerof gravity of the fixture and are, therefore,maintainedautomatically in the two extreme positions Without the aid ofpositive retaining devices; and second, to

Specification of Letters Patent.

. Patented Sept. 24,1918,

SeriaINo. 31,820. I I

incorporate in theswing joint of the fixture means whereby the wiringmay be readily led to the source of light, will be readily accessiblefor purposes of inspection or repair andv will not besubjected toobjection able twisting or bending strains during the rotation of thewires about the joint. These and other objects will be elaboratedhereinafter in connection with the detailed description of the preferredembodiments of the invention appearing in the accompanying. drawings. Inthese drawings Figure 1 is a conventional view in elevation ofafixtureconstructed in accordance with the invention, the reflector andsource of light being indicated in inverted position bydotted lines. I

Fig. 2 1s a fragmentary detail view on a somewhat larger scale of theswing joint taken on the plane indicated by the lines 2-2 of Figs. 1 and3 and looking in the direction of the arrows.

i Fig. 3 is a further detail view of the swing joint, partly in section,taken on the plane: indicated by the line 3-3 of Fig. 2 and looking inthe direction of the arrows.

Fig. 4is a detail view in perspectiveof the sleeve into which the armsof the fixture extend;

1 Fig. 5 is a detail view in perspective of one of the collars whichrest within the sleeve shown in Fig; 4.. i

Fig. 6 is a fragmentary detail View, partly in section, of a somewhatmodified form of swing joint.

Referring particularly to Fig. 1, it will be seen that there areprovided support/mg arms a on whichare carried swmg oints,

indicated generally at h, by which is formed a lunged connect1on betweenthe arms a and the fixture arms 0 which carry the lamp socket 61, sourceof light 6 (illustrated as an incandescent bulb) and a, suitablevreflector the last named elements, of course, being movable together andas a' unitary structure about the swing joints Z) with 'the'fixt'urecorms. -It will be evident that when the parts are in what may be termednormal position,

that is, with the reflector as illustrated in full lines, the rays oflight from the lamp 6 will be thrown upward to the ceiling or equivalentreflector from which they will be thrown on the objects to be lighted..When the fixture armsc-swing about the swinging joint I) untilthereflector 7 takes the position indicated in dotted lines in Fig. l, thefixture will become one of the direct lighting type and the rays oflight from the source 6 will be thrown directly upon the object to belighted. In accordance with the present invention, it is proposed tobring about the inversion of the reflector with the source of light by aconstruction which requires no special manipulation by the user, butwhich will facilitate the inversion by insuring that the fixture will bemaintained automatically in its desired position. To this end, the axis01' rotation of the fixture is coincident with the center of gravity ofthe swinging parts, so that no matter whether the fixture be in theposition indicated in full lines in Fig. 1 or that indicated in dottedlines, the tendency will be to remain in that position and not movetherefrom without the application of some little pressure. So far asconcerns this first broad object of the invention, then, it is seen toreside in the provision of a balanced invertible lighting fixture. Ofcourse, itwill be appreciated that in practice the tendency for thefixture to remain in any given position by reason of the coincidence ofthe center of gravity with the axis of swinging will be increased by thefriction necessarily present in the joint. The presence of suchfriction, however, is merely incidental to the positioning secured bythe balanced construction described.

The problem of providing an invertible lighting fixture which can bereadily moved from one extreme position to another cannot be consideredas completely solved in the absence of a suitable swinging joint topermit the rotative IHOVGIHODt of the fixture without injuriouslyaffecting the electrical wiring. Accordingly, the second broad object ofthe invention. is to provide a swinging joint for fixture of the typereferred to which shall permit the wiring to be led to the lamp withutmost facility, shall permit its inspection and repair, and shall guardagainst injury of the wire through undue twisting or bending strainsimposed thereon during adjustment of the fixture. While the specificembodiment of the improved devices for attaining these purposes mayvary, there has been illustrated in the drawings two practicalembodiments of swing joints which have proved successful in use. In thefirst of these, shown in detail in Figs. 2 and 3, the arms a and c ofthe lighting fixture are disposed substantially parallel with respect toeach other, respectively. A description of one of the joints willsufiice for both, it being understood that the axes of rotation of thetwo joints for any single fixture are coin cident. The ends of the armsa, c, extend through peripheral slots 9, g, respectively,

,formed in asleeve g and are threaded into scparatel bushings h whichare preferably slotted, as 21th, to insure a frictionalengagementbetween the outer wall thereof and. the inner wall of thesleeve gi -against which the bushings bear, as appears clearly in Fig.3. It is not necessary that the bushings h be slotted, although thiswill usually be-desirable to hold the fixture against slight accidentalmovement from its desired balanced position. The insertion of thebushings it into the sleeve g can be effected readily by slightlycompressing the bushings so that their tendency is to expand after theyare in their positions. The sleeve g may have mounted therein a threadedstud i which may extend through the sleeve and maintain the coils ofwire in substantially co-axial relationship with the axis of rotationand be retained co-axially in position with respect thereto by means ofa nut 2". threaded thereon and further by means of cylindrical bosses iand 2' formed on the reverse faces of the head of the stud i and of thenut 2'', respectively. The head of the stud and the nut z" closethe openends of the sleeve and so coverthe wires and form a sightly joint. Thecombined length ofthe two bushings h, when positioned within the sleeve.5 is preferably less than the length of this sleeve so that the nut a"may be set up without engaging the bushings. The disposition and mannerof securing the electrical wiring 7c in place in the swing joint so asto permit free rotation of the fixture thereabout can now be understoodreadily. This wiring is brought down through the hollow arm a and 1scoiled about the shank of the stud 2', the number of such coilsdepending somewhat upon the conditions of use and the character of thewire. After being thus coiled the wire is led down through the hollowarm a to the lamp socket (Z and afiixed to the electrode in a mannerwell. known. The important feature of this method ofwiring resides inthe formation-of several coilstherein along the axis of rotation of thefixture, the result secured being that the total twisting or bending towhich each coil is subjected is equal only to the normal bending towhich a single 'coil would be subjected divided by the inunstandards theunderwriters will not permit 'a conductor to be subjectedto abnormal 125recurring strains which would have a haturaltendency to break down theinsulation. Accordingly, if, a balanced invertible fixture of the typedescribed is to be a practicalsuccess, a practical means for mountingthe 0 wiring therein and permitting this rotative movement without inuring the WlI'lIlg must be employed.

In Fig. 6 there has been illustrated a somewhat modified form of a swingjoint which will serve to emphasize the fact that the invention is nottobe limited to the specific constructions illustrated herein, but thatthe two broad objects stated in the preamble may be attained by modifiedconstructions which are well within the scope of the axial relationshipwith respect to the axis of rotation, so that the electrical wiring iswhich leads down through the supporting arm a is, after being coiledaround the shank of the stud I, led through the head of the tud and intothe fixture arm C in a direction which is parallel to the axis ofrotation. This construction, while bein somewhat simpler than thatpreviously describedin that some of the parts are eliminated, has

the same advantages as those hereinbefore' pointed out in that itprevents undue twisting or bending strains being imposed on theelectrical wiring, permits this wire to be led down through the arms ofthe fixture with great facility and permits the swing joint and the wireto be inspected readily and repaired through removal of the nut I.

In use, after assembling, the improved fixture may be supposed to be insome such position as illustrated in full lines in Fig. 1, in which thearms 0 form virtually extensions of the supporting arms a. The rays oflight from the lamp 6 are thrown upward entirely by the invertedreflector If it is desired to convert the fixture into one of directlighting, the user may, by exerting slight pressure on the fixture,cause the re- Hector 0 with the light 6 to rotate about the axes of thejoints 5, the center of gravity of the swinging fixture being coincidentwith the axis of rotation, thereby insuring that the fixture shallremain in balanced position at all times and its rotation be opposedonly by the friction in the joints 5. When the reflector f has beenmoved to its inverted position, as indicated in dotted lines in Fig. l,the rays of light are thrown downward entirely. The light and thereflector tend to remain in this inverted position by reason of thebalanced condition of the fixture. During the swinging of the fixturefrom one extreme position to the other, the coils of the electric wire70 which are disposed along the axis of rotation are not subjected toundue bending or twisting strains but are deflected to an unappreciabledegree.

Permissible departures from the constructions illustrated have beenindicated hereinbefore but the, scope of the invention will rial andtending to assume a larger diameter than the internal diameter of saidcase for frictional engagement therewith.

2. In combination with relatively swinging arms, a swing joint forlighting fixtures comprising a tubular case having a plurality ofcircumferential slots and a plurality of split tubes within the saidcase and connected through said slots with said arms respectively, thesaid split tubes being of resilient material and tending to assume alarger diameter than the internal diameter of said case for frictionalengagement therewith, and a stud supported within the split tubes andadapted to support the electric wires for the fixture in coiledposition.

3. A swing joint for lighting fixtures comprising a sleeve having slotsformed in its periphery to receive the supporting arms 7 ERNEST ownrrn.

Copies of this patent may be'obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G. i

